The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment of any royalty thereon.
This invention relates to a 589 nm laser and more particularly to such laser in Pr-doped glass.
Satellite communication systems employ lasers at 589 nm (sodium D line) to generate a xe2x80x9cbright starxe2x80x9d reference used for correcting atmospheric distortion. This wavelength is currently available only from large-scale laser systems such as dye, OPO or sum-frequency Nd-YAG. However, such lasers are unsuitable for small-scale or mobile communication systems. Pr3+-doped fluorozirconate ZBLAN glass has been extensively investigated for both a 1.3 xcexcm amplifier and as a laser at red, green and blue wavelengths. Lasing at visible wavelengths originates from the 3P1+3P0 levels. Tunable lasing at 599-618 nm has been demonstrated in both direct-pumped and upconversion lasers, but did not extend to 589 nm. That is, Pr3+-doped fluorozirconate ZBLAN glass is known to lase at 601-618 nm but lasing at 589 nm can not be achieved in this host. Thus, Pr3+ emission is known to be strongly host-dependent.
In the prior art are U.S. Pat. No. 6,061,170 to Rice et al (2000) and U.S. Pat. No. 5,832,006 to Rice et al (1998), which patents however, are directed to frequency laser amplifier arrays with no mention of a glass host doped with PrF for lasing at 589 nm, to generate a bright star reference therein.
Accordingly, there is need and market to identify a suitable host for the desired lasing to overcome the above prior art shortcomings.
There has now been discovered a suitable host to achieve lasing at 589 nm.
Broadly the present invention provides a lasing host comprising a fluoroaluminate glass doped with PrF3 or Pr3+ ions for lasing at 589 nm.
The invention further provides a method for increasing the emissions of the above fluoroaluminate glass, comprising heating the glass sufficiently to thermally enhance 589 nm fluorescence from Pr3+ ions in the glass.
Also provided is a method for thermally enhancing 589 nm fluorescence from Pr3+ ions in the above glass, wherein the glass is heated in order to increase the thermal population of the ions at the 3P1 energy level, which level is described below.
The present invention has been described, in part, in a Paper published in the Journal of Luminescence, entitled Pr3+-doped fluoride glass for a 589 nm fibre laser, published October 2000 by Mira Naftaly et al, which Paper is incorporated herein by reference.